It is well known to those skilled in the art that aromatic hydrocarbons are a class of very important industrial chemicals which find a variety of uses in petrochemical industry. It is also well known to those skilled in the art that catalytically cracking gasoline range hydrocarbons produces benzene, toluene, xylenes, or combinations of two or more thereof which are hereinafter referred to as BTX or C.sub.6 to C.sub.8 aromatic hydrocarbons, in the presence of catalysts which contain a zeolite. The product of this catalytic cracking process contains a multitude of hydrocarbons including unconverted C.sub.5 + alkanes, C.sub.5 + alkenes, C.sub.5 + cycloalkanes, or combinations of two or more thereof; BTX; lower alkanes such as methane, ethane, and propane; and lower alkenes such as ethylene and propylene.
In a fluidized catalytic cracking (FCC) process, one of the product fractions is fuel oil fraction which contains about over 90 weight % of polyaromatic compounds having 10 to about 25 carbon atoms per molecule. The fuel oil fraction generally has low value as compared to other petrochemicals, especially BTX. Therefore, it is highly desirable to convert fuel oil to benzene, xylenes, toluene, or combinations thereof.
Furthermore, the fuel oil generally comprises a sulfur compound. If a sulfur compound is not removed in a hydrocarbon conversion process, the sulfur compound will be in the product stream thereby decreasing the value of the hydrocarbon conversion product. Accordingly, there is a need to also reduce the sulfur content in a hydrocarbon conversion product.
Therefore, development of a catalyst and a process for improving the conversion of a hydrocarbon such as fuel oil, especially in the presence of a sulfur compound, to the more valuable benzene, a xylene, or combinations thereof would be a significant contribution to the art and to the economy.